The field of the invention is laboratory procedures and the invention relates more particularly to a procedure for determining the T4/T8 cell ratio which is often referred to as the "helper/suppressor" ratio.
In the past, a lengthy procedure was used requiring in excess of two hours to perform. More specifically, the prior art procedure started by transferring a 250 microliter sample of anticoagulant-treated blood into a centrifuge tube where 2 milliliters of a lysing reagent were added. The lysed blood mixture was incubated for five minutes and a cell wash solution was then added to the resulting lysed sample. The sample was then centrifuged for three minutes at 150.times.G. The supernatant fluid was then decanted and a new 8 milliliter portion of wash solution was added and the fluid was mixed and once again centrifuged for three minutes at 150.times.G. After a second decanting step, the pellet was suspended in 10 milliliters of wash solution and 200 microliters of colored bead solution was added. The fluid was then centrifuged again for three minutes at 150.times.g and incubated at ten minutes at room temperature. The supernatant fluid was then decanted and the pellet was resuspended and transferred to a microscope slide.